Japanese Patent Application Publication No. 2001-286122 (JP2001-286122A) discloses a linear synchronous motor comprising a stator and a mover that linearly moves relative to the stator. The mover includes a direct drive shaft reciprocating in an axial direction and an array of permanent magnets or a permanent magnet array including a plurality of permanent magnets fixed to the direct drive shaft. The stator includes a plurality of annular windings and a stator core unit having formed a slot for receiving each of the plurality of annular windings. The annular windings are each formed of an annularly wound winding conductor and are disposed to enclose the mover. The stator core unit is constituted from a plurality of stator core divided bodies assembled with each other in the axial direction. The stator core divided bodies are formed by cutting work, and each include a magnetic pole portion facing the permanent magnet array of the mover and a yoke constituting portion which is combined with another stator core divided body to constitute a yoke magnetically connecting the magnetic pole portions. One annular winding is disposed between two adjacent magnetic pole portions.
Existing linear synchronous motors have an issue that the assembling of the stator core unit is complicated. To cope with the issue, a plurality of magnetic pole portions may be constituted from a pair of end annular magnetic pole portions located at axial ends and one or more intermediate annular magnetic pole portions located between the pair of end annular magnetic pole portions, and have a yoke assembly connected to the intermediate annular magnetic pole portions. However, it is complicated to connect the intermediate annular magnetic pole portions and the yoke assembly is complicated.
An object of the present invention is to provide a linear synchronous motor in which it is easy to connect an intermediate annular magnetic pole portion and a yoke assembly.
Another object of the present invention is to provide a linear synchronous motor in which positioning of intermediate annular magnetic pole portions may be determined.
Still another object of the present invention is to provide a linear synchronous motor in which an axial dimension of the linear synchronous motor may be reduced compared with the prior art and a lubricant applied to a linear bearing may be prevented from adhering to a magnetic pole surface of an annular magnetic pole portion or members around a direct drive shaft.
Yet another object of the present invention is to provide a linear synchronous motor in which molding process may be simplified, and heat of the motor may be dissipated through a peripheral wall portion.
Even another object of the present invention is to provide a linear synchronous motor for which it is not necessary to produce an end annular magnetic pole portion corresponding to a different model.
Still another object of the present invention is to provide a linear synchronous motor in which manufacturing cost of a stator may be reduced, and magnetic loss may be reduced, and iron loss may also be suppressed.
Yet another object of the present invention is to provide a linear synchronous motor in which generation of iron loss can be suppressed while maintaining an occupied volume of an excitation winding.
Even another object of the present invention is to provide a manufacturing method of a linear synchronous motor which does not need of providing a positioning means, such as a fitting structure, for positioning a plurality of annular magnetic pole portions in members of the motor.